 /*******************************************************************************
  * Copyright (c) 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  ******************************************************************************/
 package org.eclipse.ui.internal.commands.ws;

 import java.lang.reflect.InvocationTargetException ;
 import java.lang.reflect.Method ;
 import java.util.Map ;

 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.ui.commands.ExecutionException;

 /**
  * This handler is an adaptation of the widget method handler allowing select
  * all to work even in some cases where the "selectAll" method does not exist.
  * This handler attempts to use "getTextLimit" and "setSelection" to do select
  * all. If this doesn't work, then it finally fails.
  *
  * @since 3.0
  */
 public class SelectAllHandler extends WidgetMethodHandler {

     /**
      * The parameters for a single point select all.
      */
     private static final Class [] METHOD_PARAMETERS = { Point.class };

     /**
      * @see org.eclipse.ui.commands.IHandler#execute(Map)
      */
     public Object execute(Map parameterValuesByName) throws ExecutionException {
         final Method methodToExecute = getMethodToExecute();
         if (methodToExecute != null) {
             try {
                 final Control focusControl = Display.getCurrent()
                         .getFocusControl();
                 final int numParams = methodToExecute.getParameterTypes().length;

                 if (numParams == 0) {
                     // This is a no-argument selectAll method.
 methodToExecute.invoke(focusControl, null);

                 } else if (numParams == 1) {
                     // This is a single-point selection method.
 final Method textLimitAccessor = focusControl.getClass()
                             .getMethod("getTextLimit", NO_PARAMETERS); //$NON-NLS-1$
 final Integer textLimit = (Integer ) textLimitAccessor
                             .invoke(focusControl, null);
                     final Object [] parameters = { new Point(0, textLimit
                             .intValue()) };
                     methodToExecute.invoke(focusControl, parameters);

                 } else {
                     /*
                      * This means that getMethodToExecute() has been changed,
                      * while this method hasn't.
                      */
                     throw new ExecutionException(
                             "Too many parameters on select all", new Exception ()); //$NON-NLS-1$

                 }

             } catch (IllegalAccessException e) {
                 // The method is protected, so do nothing.

             } catch (InvocationTargetException e) {
                 throw new ExecutionException(
                         "An exception occurred while executing " //$NON-NLS-1$
 + getMethodToExecute(), e.getTargetException());

             } catch (NoSuchMethodException e) {
                 // I can't get the text limit. Do nothing.

             }
         }

         return null;
     }

     /**
      * Looks up the select all method on the given focus control.
      *
      * @return The method on the focus control; <code>null</code> if none.
      */
     protected Method getMethodToExecute() {
         Method method = super.getMethodToExecute();

         // Let's see if we have a control that supports point-based selection.
 if (method == null) {
             final Control focusControl = Display.getCurrent().getFocusControl();
             try {
                 method = focusControl.getClass().getMethod("setSelection", //$NON-NLS-1$
 METHOD_PARAMETERS);
             } catch (NoSuchMethodException e) {
                 // Do nothing.
 }
         }

         return method;
     }

     /**
      * @see org.eclipse.core.runtime.IExecutableExtension#setInitializationData(org.eclipse.core.runtime.IConfigurationElement,
      * java.lang.String, java.lang.Object)
      */
     public void setInitializationData(IConfigurationElement config,
             String propertyName, Object data) {
         // The name is always "selectAll".
 methodName = "selectAll"; //$NON-NLS-1$
 }
 }
